var nav = document.querySelectorAll('.nav > li');
var main = document.querySelectorAll('.main > div');

for(var i = 0;i<nav.length;i++){
	nav[i].addEventListener('click',function(){
		for(var j = 0; j<nav.length;j++){
			nav[j].classList.remove('active');
		}
		console.log(this);
		console.log(this.index);
		this.classList.add('active');
		main[this.index].classList.add('active');
	})
}